ALSA: usx2y: Fix unlocked snd_pcm_stop() call

snd_pcm_stop() must be called in the PCM substream lock context.

Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/usx2y/usbusx2yaudio.c

@@ -273,7 +273,11 @@ static void usX2Y_clients_stop(struct usX2Ydev *usX2Y)
 		struct snd_usX2Y_substream *subs = usX2Y->subs[s];
 		if (subs) {
 			if (atomic_read(&subs->state) >= state_PRERUNNING) {
+				unsigned long flags;
+
+				snd_pcm_stream_lock_irqsave(subs->pcm_substream, flags);
 				snd_pcm_stop(subs->pcm_substream, SNDRV_PCM_STATE_XRUN);
+				snd_pcm_stream_unlock_irqrestore(subs->pcm_substream, flags);
 			}
 			for (u = 0; u < NRURBS; u++) {
 				struct urb *urb = subs->urb[u];